Lesson Title: Berry wonderful DNA (extraction) lab
State Standards: GLEs/GSEs
GSEs: LS1 (9-11)-1a Students demonstrates understanding of structure and function-survival requirements by: explaining the relationships between and amongst the specialized structures of the cell and their functions (e.g.- transport of materials, energy transfer, protein building, waste disposal, information feedback, and even movement)
LS1 (9-11)-2 Students demonstrate an understanding of the molecular basis for heredity (2a) describing the DNA structure and relating the DNA sequence to the genetic code. (2b) explaining how DNA may be altered and how this affects genes/heredity (e.g. substitution, insertion, or deletion).
National Standards:
Context of Lesson:
Previously, students learned about the structure of DNA, and its variety of pieces. They also covered mitosis, so they should understand the different cell-processes from previous units as well.
This lesson is meant to be a more hands-on representation of DNA within the cells, of how DNA is present in cells and give just a chance to "see" it with their own eyes.
Students will be challenged at a level of strategic thinking, in that using the different fruits given, they will try to determine why particular fruits have "more" DNA than others. They are required to connect between what they know about DNA and its purpose in an organism, and what they know (or think they know!) about fruit.
Prerequisite Knowledge:
Students know about different parts of cells from previous lessons and units, and had a lesson about Mitosis and the structure of DNA.
They also should know how to behave properly within a laboratory setting.
Plans for Differentiating Instruction:
- higher level learners are given a strawberry exit sheet- with more challenging questions
- lower level learners are given a strawberry exit sheet- with less challenging questions
Accommodations and modifications:
- modifications: students that cause trouble within the class will be given an essay question, as will those who start to ask for extra credit
Environmental factors:
This particular lesson is set up to be held within a laboratory environment, where students will be provided the materials and given a demonstration.
ALSO: the isopropanol is to be spoken of as ISOPROPANOL only- NOT ALCOHOL. We don't need students drinking the laboratory materials. You should advise against drinking the chemicals explicitly.
Materials:
- Strawberries of varying sizes
- Dishwashing detergent
- Rubbing alcohol
- clear glass containers such as beakers or cups (1 per student)
- graphic organizer on strawberry DNA extraction
- 1 plastic bag per student (bring extras!)
Objectives:
At the end of the lesson, students will be able to recognize, through successful performance and observations of the experiment- that DNA is present in all cells, and that there may be a difference in the amount of DNA contained within different organisms (plants in this case), for different reasons!
Instruction:
(Key to Lesson Plan's Shorthand) TA: Teacher action TV: Teacher words SV: Student voice (anticipated responses) SA: Student action (anticipated action or movement) E: event/ wait time/ travel time, it should be emphasized. Italics!: These emphasize specific "reasons" for the action, if they're not otherwise apparent. Also known as "stealth objectives", a deeper reason for saying or acting as you do.
Opening:
TA: Collect mitosis coloring sheets, greet everyone who is coming in, hand everyone a strawberry, of varying size. What are your instructions for the strawberry. If you don't say something immediately, your laboratory materials with be eaten. As you're collecting, check the names at the top of the papers, to reiterate in your mind of recalling everyone's names correctly.You should know their names already. Focus on this in your first days back at the school. E: Wait for students to sit down, bring everyone's attention back TV: Okay, so how was the coloring sheet last night? SV: Good good You need to think of questions that require more useful answers. "Name one characteristic of mitosis that is the same/ different from meiosis." Some kind of conversation going here, go with class' reaction and if they need some push! TV: So, someone please tell me, what exactly does mitosis do. SA/V: Hands raise; students say "mitosis is cell division" Or something of the sort, correct and praise as needed if at all. TV: Okay, say that again NAME OF CHILD* so that everyone could hear it! * Use the student's name so that you can remember!
Also, only say this if actual answers are given! Otherwise, continue TV: Yes exactly! So, mitosis is cell division resulting in TWO daughter cells with the same number and kind of chromosomes as the parent cell.
Repeat after me- "mitosis is- Cell division resulting in TWO daughter cells with the same number of and kind of chromosomes as the parent cell." Again- one more time! Use EMPHASIS and INFLECTION and ENTHUSIASM!
Repetitionis a wonderful tool to remember things... and using your voice makes it much more real for the students, (especially those students who like to talk.)
Engagement:
TV: Now I wonder... excuse me,(pick a student) NAME*, may I borrow your fruit for a moment? * TRY TO REMEMBER THEIR NAMES! (CRUCIAL) Focus on finding a student who is less involved in the class, especially perhaps one who is sitting near the back! Try to catch their interest with being 'puzzled' as you look at the different fruits near them SA: Student donates fruit reluctantly or joyfully or apathetically. TV: We've learned about mitosis, and the structure of DNA. Wait, what is mitosis again? SV/TV: "Mitosis is cell division resulting in TWO daughter cells with the same number and kind of chromosomes as the parent cell" TV: Okay thanks, just checking. TA: Look thoughtfully at the fruit as you walk around the classroom. TV: Then, there must be a bunch of cells in this strawberry, dividing everywhere. What would those cells be doing to the fruit? At this point, the questions are posed to see what exactly students understand about mitotic cell division.
Why are they dividing? SV: To replace the old cells, to keep growing TV: Right, so, now I wonder, do smaller strawberries have less DNA or more DNA then? Or do the bigger ones? Do you think there is a size limit to the berry and DNA- for example does the DNA break down after the cell is made, so the berry can just be food storage (like an egg yolk) for the seeds inside?
Today, we're going to see what we can uncover. Nice explanation of laboratory's goal. TA: Start handing out lab sheets TV: Today, we're taking the DNA out of these berries here, with simple ingredients that you'd find say- in your kitchen. TV/A: Okay- lets go to the lab! Head off to the lab! The lab at South Kingstown HS is separate from the classrooms, and is shared between classes.
once everyone is in the lab, call them over to the main bench to watch the procedure DEMONSTRATED really quickly.
MENTION THIS: TV: Also, be sure that you WEIGH your strawberries first beforehand, you need to take data from FOUR other lab groups besides your own and the control which I have shown you. TV: Now, ANYONE, I repeat again- ANYONE caught eating or drinking ANYTHING in this lab, we are scientists here, so this includes even the strawberries, will be given a zero pending a discussion after class, and made to work on the worksheet themselves over here (gestures to spare chair) or extra busy work. Busy work for those students who decide to make some kind of bubbly strawberry daquiri- an Essay! "You are a reporter, wondering what makes these strawberries so HUGE compared to wild strawberries. You have also heard rumors of genetically modified strawberries from other people around. Write a short reporting article, in 500 words or less, about what you have discovered and what the public should know. Use reliable sources please!" Give them a few days to complete it!
Personally, I would not threaten because it begs the students who are trying to get your attention through negative means to call your bluff. Instead, lay down the law as if its not a choice and you will not consider it being any other way. If you violate my policy, then you will be in violation of your lab safety contract and will have to sit down and we'll have to conference with your parents before you can resume labs. Is it a good idea to assign extra learning tasks (essays) as punishment? What is the message you're sending?
Teacher trick: Be quietly assertive and most students will comply. Never threaten what you aren't prepared to do. Always follow through immediately (but calmly) if someone violates your boundaries. Avoid causing a commotion or losing focus on learning activity.
Are you going to show the procedure video?
TA/V: As students begin procedure, continue to walk around and assist as needed, answer questions throughout. There might be some students who are confused, or there might be a portion of the experiment that was not well explained. In this potential unfortunate case, pause and clarify to the whole class!
What will you be doing as you walk around? What questions can you ask to help students connect their actions with the topic of meiosis? You might be surprised at how students keep "textbook" knowledge separate from what they are doing. You help them to join the two with your questions.
Closure:
Make certain that all of the students have gathered the data they need from the other students. ASK a student if you can take one of their beakers of DNA-goo to use as a demonstration- make sure that it is a clear and well-done sample!
(Ten minutes to spare!) TV: Okay, so I would like everyone to start cleaning up, dump out the berry-goo please, and rinse out your beakers.
Before you leave, lets go over a few things really quick.
"mitosis is- Cell division resulting in TWO daughter cells with the same number of and kind of chromosomes as the parent cell."
So what you've been looking at, in all of the beakers, is really the DNA! Where in the cell did it come from? SV: It came from inside the cells Will you show a representation of the cell here? TV: YES! Exactly! Inside the nucleus! The first time, we crushed the fruit, why? SV: To destroy the cells What part of the cells? TV: And then, we added the soap to- (this one is a bit harder, think nucleus!) SV: Disintegrate the nucleus! TV: Exactly! So, before you go, I would like you to take this, and start working on it. Either give this as homework, or give it as an exit sheet, depending on the time leftover! TA: Hand out Strawberry Exit Sheets, collect Lab sheets from everyone as they leave. What are the exit questions?
Assessment:
Homework from the night before (mitosis coloring sheets)
Lab data sheets that were completed in class
- students have completed the sheets with little or no data taken down, nor did they complete the lab. Behavior and technique are poor, if notable at all.
Student Work Sample 2 – Proficient:
- students here completed the sheets, although there is some data taken down, they did not completely finish the lab- such as taking down the weights of the fruits they observed, and did not finish the observations; lab technique and behavior is average.
Student Work Sample 3 – Exceeds Proficiency:
- students in this category completed the sheets, with lots of thoughtful data, remembered to take down at least six different observations, laboratory technique and behavior is excellent
Lesson Plan
Lesson Title: Berry wonderful DNA (extraction) lab
State Standards: GLEs/GSEs
GSEs: LS1 (9-11)-1a Students demonstrates understanding of structure and function-survival requirements by: explaining the relationships between and amongst the specialized structures of the cell and their functions (e.g.- transport of materials, energy transfer, protein building, waste disposal, information feedback, and even movement)LS1 (9-11)-2 Students demonstrate an understanding of the molecular basis for heredity (2a) describing the DNA structure and relating the DNA sequence to the genetic code. (2b) explaining how DNA may be altered and how this affects genes/heredity (e.g. substitution, insertion, or deletion).
National Standards:
Context of Lesson:
Previously, students learned about the structure of DNA, and its variety of pieces. They also covered mitosis, so they should understand the different cell-processes from previous units as well.This lesson is meant to be a more hands-on representation of DNA within the cells, of how DNA is present in cells and give just a chance to "see" it with their own eyes.
Sources: WonderHowTo.com, "How to extract DNA from strawberries at home" Part I, Part II
Another resource: http://www.thetech.org/genetics/medicine.php -
Opportunities to Learn
Depth of Knowledge:
Students will be challenged at a level of strategic thinking, in that using the different fruits given, they will try to determine why particular fruits have "more" DNA than others. They are required to connect between what they know about DNA and its purpose in an organism, and what they know (or think they know!) about fruit.Prerequisite Knowledge:
Students know about different parts of cells from previous lessons and units, and had a lesson about Mitosis and the structure of DNA.They also should know how to behave properly within a laboratory setting.
Plans for Differentiating Instruction:
- higher level learners are given a strawberry exit sheet- with more challenging questions- lower level learners are given a strawberry exit sheet- with less challenging questions
Accommodations and modifications:
- modifications: students that cause trouble within the class will be given an essay question, as will those who start to ask for extra creditEnvironmental factors:
This particular lesson is set up to be held within a laboratory environment, where students will be provided the materials and given a demonstration.ALSO: the isopropanol is to be spoken of as ISOPROPANOL only- NOT ALCOHOL. We don't need students drinking the laboratory materials. You should advise against drinking the chemicals explicitly.
Materials:
- Strawberries of varying sizes- Dishwashing detergent
- Rubbing alcohol
- clear glass containers such as beakers or cups (1 per student)
- graphic organizer on strawberry DNA extraction
- 1 plastic bag per student (bring extras!)
Objectives:
At the end of the lesson, students will be able to recognize, through successful performance and observations of the experiment- that DNA is present in all cells, and that there may be a difference in the amount of DNA contained within different organisms (plants in this case), for different reasons!Instruction:
(Key to Lesson Plan's Shorthand)TA: Teacher action
TV: Teacher words
SV: Student voice (anticipated responses)
SA: Student action (anticipated action or movement)
E: event/ wait time/ travel time, it should be emphasized.
Italics!: These emphasize specific "reasons" for the action, if they're not otherwise apparent. Also known as "stealth objectives", a deeper reason for saying or acting as you do.
Opening:
TA: Collect mitosis coloring sheets, greet everyone who is coming in, hand everyone a strawberry, of varying size. What are your instructions for the strawberry. If you don't say something immediately, your laboratory materials with be eaten.As you're collecting, check the names at the top of the papers, to reiterate in your mind of recalling everyone's names correctly. You should know their names already. Focus on this in your first days back at the school.
E: Wait for students to sit down, bring everyone's attention back
TV: Okay, so how was the coloring sheet last night?
SV: Good good You need to think of questions that require more useful answers. "Name one characteristic of mitosis that is the same/ different from meiosis."
Some kind of conversation going here, go with class' reaction and if they need some push!
TV: So, someone please tell me, what exactly does mitosis do.
SA/V: Hands raise; students say "mitosis is cell division"
Or something of the sort, correct and praise as needed if at all.
TV: Okay, say that again NAME OF CHILD* so that everyone could hear it!
* Use the student's name so that you can remember!
Also, only say this if actual answers are given! Otherwise, continue
TV: Yes exactly! So, mitosis is cell division resulting in TWO daughter cells with the same number and kind of chromosomes as the parent cell.
Repeat after me- "mitosis is- Cell division resulting in TWO daughter cells with the same number of and kind of chromosomes as the parent cell." Again- one more time!
Use EMPHASIS and INFLECTION and ENTHUSIASM!
Repetitionis a wonderful tool to remember things... and using your voice makes it much more real for the students, (especially those students who like to talk.)
Engagement:
TV: Now I wonder... excuse me,(pick a student) NAME*, may I borrow your fruit for a moment?* TRY TO REMEMBER THEIR NAMES! (CRUCIAL)
Focus on finding a student who is less involved in the class, especially perhaps one who is sitting near the back!
Try to catch their interest with being 'puzzled' as you look at the different fruits near them
SA: Student donates fruit reluctantly or joyfully or apathetically.
TV: We've learned about mitosis, and the structure of DNA. Wait, what is mitosis again?
SV/TV: "Mitosis is cell division resulting in TWO daughter cells with the same number and kind of chromosomes as the parent cell"
TV: Okay thanks, just checking.
TA: Look thoughtfully at the fruit as you walk around the classroom.
TV: Then, there must be a bunch of cells in this strawberry, dividing everywhere. What would those cells be doing to the fruit?
At this point, the questions are posed to see what exactly students understand about mitotic cell division.
Why are they dividing?
SV: To replace the old cells, to keep growing
TV: Right, so, now I wonder, do smaller strawberries have less DNA or more DNA then? Or do the bigger ones? Do you think there is a size limit to the berry and DNA- for example does the DNA break down after the cell is made, so the berry can just be food storage (like an egg yolk) for the seeds inside?
Today, we're going to see what we can uncover. Nice explanation of laboratory's goal.
TA: Start handing out lab sheets
TV: Today, we're taking the DNA out of these berries here, with simple ingredients that you'd find say- in your kitchen.
TV/A: Okay- lets go to the lab!
Head off to the lab! The lab at South Kingstown HS is separate from the classrooms, and is shared between classes.
once everyone is in the lab, call them over to the main bench to watch the procedure DEMONSTRATED really quickly.
MENTION THIS:
TV: Also, be sure that you WEIGH your strawberries first beforehand, you need to take data from FOUR other lab groups besides your own and the control which I have shown you.
TV: Now, ANYONE, I repeat again- ANYONE caught eating or drinking ANYTHING in this lab, we are scientists here, so this includes even the strawberries, will be given a zero pending a discussion after class, and made to work on the worksheet themselves over here (gestures to spare chair) or extra busy work.
Busy work for those students who decide to make some kind of bubbly strawberry daquiri- an Essay! "You are a reporter, wondering what makes these strawberries so HUGE compared to wild strawberries. You have also heard rumors of genetically modified strawberries from other people around. Write a short reporting article, in 500 words or less, about what you have discovered and what the public should know. Use reliable sources please!" Give them a few days to complete it!
Personally, I would not threaten because it begs the students who are trying to get your attention through negative means to call your bluff. Instead, lay down the law as if its not a choice and you will not consider it being any other way. If you violate my policy, then you will be in violation of your lab safety contract and will have to sit down and we'll have to conference with your parents before you can resume labs. Is it a good idea to assign extra learning tasks (essays) as punishment? What is the message you're sending?
Teacher trick: Be quietly assertive and most students will comply. Never threaten what you aren't prepared to do. Always follow through immediately (but calmly) if someone violates your boundaries. Avoid causing a commotion or losing focus on learning activity.
Are you going to show the procedure video?
TA/V: As students begin procedure, continue to walk around and assist as needed, answer questions throughout.
There might be some students who are confused, or there might be a portion of the experiment that was not well explained. In this potential unfortunate case, pause and clarify to the whole class!
What will you be doing as you walk around? What questions can you ask to help students connect their actions with the topic of meiosis? You might be surprised at how students keep "textbook" knowledge separate from what they are doing. You help them to join the two with your questions.
Closure:
Make certain that all of the students have gathered the data they need from the other students. ASK a student if you can take one of their beakers of DNA-goo to use as a demonstration- make sure that it is a clear and well-done sample!(Ten minutes to spare!)
TV: Okay, so I would like everyone to start cleaning up, dump out the berry-goo please, and rinse out your beakers.
Before you leave, lets go over a few things really quick.
"mitosis is- Cell division resulting in TWO daughter cells with the same number of and kind of chromosomes as the parent cell."
So what you've been looking at, in all of the beakers, is really the DNA! Where in the cell did it come from?
SV: It came from inside the cells
Will you show a representation of the cell here?
TV: YES! Exactly! Inside the nucleus! The first time, we crushed the fruit, why?
SV: To destroy the cells What part of the cells?
TV: And then, we added the soap to- (this one is a bit harder, think nucleus!)
SV: Disintegrate the nucleus!
TV: Exactly! So, before you go, I would like you to take this, and start working on it.
Either give this as homework, or give it as an exit sheet, depending on the time leftover!
TA: Hand out Strawberry Exit Sheets, collect Lab sheets from everyone as they leave. What are the exit questions?
Assessment:
Homework from the night before (mitosis coloring sheets)Lab data sheets that were completed in class
For the next day- collect berry wonderful exit sheets
Reflections
(only done after lesson is enacted)Student Work Sample 1 – Approaching Proficiency:
- students have completed the sheets with little or no data taken down, nor did they complete the lab. Behavior and technique are poor, if notable at all.Student Work Sample 2 – Proficient:
- students here completed the sheets, although there is some data taken down, they did not completely finish the lab- such as taking down the weights of the fruits they observed, and did not finish the observations; lab technique and behavior is average.Student Work Sample 3 – Exceeds Proficiency:
- students in this category completed the sheets, with lots of thoughtful data, remembered to take down at least six different observations, laboratory technique and behavior is excellent